SOLUTION: A box contains cards with one question on each card There are 4 categories of questions each category has some easy and some difficult questions This table shows the probabili

Question 854776: A box contains cards with one question on each card
There are 4 categories of questions
each category has some easy and some difficult questions
This table shows the probability of selecting a card at random
CATEGORY
Music
Sport
History
Nature
EASY
0.2
0.2
0.1
0.15
DIFFICULT
0.15
0.1
0.05
0.05
(A)I am going to take one card at random from the box.
What is the probability that it will be:
A HISTORY QUESTION?
Is the answer 0.15
AN EASY QUESTION?
Is the answer 0.65
(B)There are 40 cards in the box.
How many of these are MUSIC questions?
Is the answer 3

Found 2 solutions by richwmiller, ewatrrr:
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
your answers are good except for the number of music questions.
.20+.15=.35
.35*40=14 music questions
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!

Hi,
Think it is easier to view data like this:
type EASY DIFF T
Music 0.2 0.15 0.35
Sport 0.2 0.1 0.3
History 0.1 0.05 0.15
Nature 0.15 0.05 0.2
Total .65 .35 1.00
(A)I am going to take one card at random from the box.
What is the probability that it will be:
A HISTORY QUESTION?
Is the answer 0.15
AN EASY QUESTION?
Is the answer 0.65
(B)There are 40 cards in the box.
How many of these are MUSIC questions
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